Electro valves buzzing after switch off

[nigxl]

Have a bank of 3 EVs on my 2001 90bhp Hdi. They all seem to be buzzing once the car is shut down as if the pressure is reducing slowly. This lasts for about a minute before they shut up. Could this be a leaking diaphragm inside one of them or is this normal?
Car could do with a bit more power actually, suspecting one or more of the solenoids needs a look at.

[D4B]

My 2002 110 Hdi does that too, is it normal I don't know.... do others do this too?

What do these valves do?

[steve_earwig]

They all do that sir. The electrovalves run the turbo, egr and air doser on those so inflicted.

[D4B]

Thanks Steve - that clears that mystery up

[Doggy]

Oddly, 2.2's don't.

Perhaps because there's so many e/v's it would flatten the battery?

[steve_earwig]

Maybe they all have too many vacuum leaks...

[nigxl]

Thanks for that